Syquest Technology, the present assignee has a number of patents issued which deal with removable media disc drives. These patents include by way of example, U.S. Pat. No. 4,504,879, issued Mar. 12, 1985 entitled "DISC CARTRIDGE ARRANGEMENT WITH DOOR ACTUATED MAGNETIC HEAD MOVEMENT LINKAGE" and U.S. Pat. No. 4,683,506, issued Jul. 28, 1987 entitled "DISC DRIVE ARRANGEMENT FOR A HARD DISC CARTRIDGE WITH A READ/WRITE HEAD RETRACT MECHANISM". With these drives, the drive itself includes a spindle motor for causing the disc located in a removable cartridge to spin. The disc is mounted in the removable cartridge with a hub assembly which includes a seating mechanism for causing the hub to engage onto the spindle of the spindle motor once the cartridge is inserted into the drive.
The spindle motor is in such arrangements are generally of the radial gap variety. A discussion of radial gap motors can be obtained in U.S. Pat. No. 4,745,345. Other types of disc drives, such as floppy disc drives use an axial gap motor positioned in the drive. A discussion of axial drive motors can also be obtained from the above U.S. Pat. No. 4,745,345. Additionally, VCR use such axial gap motors for the spindle motor.
With respect to the removable media disc drive, care must be taken in the design of the spindle motor, the hub arrangement, and seating arrangement which allows the removable media to be seated on the spindle of the spindle motor in order to minimize the effect of wobble or runout. Wobble or runout occur due to the fact that the centerline of the disc is not aligned with the centerline of the spindle motor. Further, additional concerns arise with the repeatability of positioning the disc and hub arrangement in the same manner on the same or different spindle of the same or different disc drive.
Further with such arrangements, as the hub and seating arrangements must extend through the cartridge housing, there is always the possibility that dust can be drawn in at the center of the cartridge when the disc is spinning.
Further with such arrangements, the cartridge receiving mechanism, which receives and positions the cartridge onto the spindle of the spindle motor in the disc drive must by nature be complex as it is required in some manner to accept the cartridge and then position the cartridge over the spindle motor without contacting the upstanding spindle. Then the receiving mechanism must set the cartridge down onto the spindle of the spindle motor. For removing the cartridge, the reverse process must be accomplished.